Watermark from buffer

jimp-watermark.js

const jimp = require('jimp')
const { readFile, writeFile } = require('fs')

readFile('maxresdefault.jpg', function (err, bufferImage) {
  readFile('logo100.png', function (err, bufferLogo) {
    jimp.read(bufferImage).then(jImage => {
      jimp.read(bufferLogo).then(jLogo => {
        jImage.composite(
          jLogo,
          jImage.getWidth() - jLogo.getWidth() - 10,
          jImage.getHeight() - jLogo.getHeight() - 10,
          {
            mode: jimp.BLEND_SOURCE_OVER,
            opacityDest: 1,
            opacitySource: 0.5
          })
        jImage.write('output.png')
      })
    })
  })
})